test errors

src/lexer.rs

@@ -250,20 +250,38 @@ impl<'a> Lexer<'a> {
     }
 
     fn lex_num(&mut self) -> TokenKind {
-        let mut string = String::with_capacity(99);
+        let mut whole = String::new();
         while let Some(c) = self.buf.peek() {
-            if !c.is_numeric() && c != &'.' {
+            if !c.is_numeric() {
                 break;
             }
-            let tok = self
-                .buf
-                .next()
-                .expect("this is impossible because we have already peeked");
+            let tok = self.buf.next().unwrap();
             self.pos.next_char();
-            string.push(tok);
+            whole.push(tok);
         }
 
-        TokenKind::Number(string)
+        let mut dec = String::new();
+
+        if self.buf.peek() == Some(&'.') {
+            self.buf.next();
+            dec.push('.');
+            while let Some(c) = self.buf.peek() {
+                if !c.is_numeric() {
+                    break;
+                }
+                let tok = self.buf.next().unwrap();
+                self.pos.next_char();
+                dec.push(tok);
+            }
+        }
+
+        if dec.len() == 1 {
+            return TokenKind::Error("Expected digit.".into());
+        }
+
+        whole.push_str(&dec);
+
+        TokenKind::Number(whole)
     }
 
     fn lex_hash(&mut self) -> TokenKind {

tests/error.rs

@@ -0,0 +1,9 @@
+#![cfg(test)]
+
+#[macro_use]
+mod macros;
+
+error!(
+    nothing_after_decimal,
+    "a {\n  color: 1.;\n}\n", "Error: Expected digit."
+);

tests/macros.rs

@@ -33,3 +33,17 @@ macro_rules! test {
         }
     };
 }
+
+#[macro_export]
+macro_rules! error {
+    ($func:ident, $input:expr, $err:expr) => {
+        #[test]
+        #[allow(non_snake_case)]
+        fn $func() {
+            match grass::StyleSheet::new($input) {
+                Ok(..) => panic!("did not fail"),
+                Err(e) => assert_eq!($err, e.to_string().as_str()),
+            }
+        }
+    };
+}